Overview

7705 SAR QoS policies are applied on service ingress, service egress, and network interfaces. The service ingress and service egress points may be considered as the network QoS boundaries for the service being provided.

The QoS policies define:

• classification rules for how traffic is mapped to forwarding classes

• how forwarding classes are aggregated under queues

• the queue parameters used for policing, shaping, and buffer allocation

• QoS marking/interpretation

There are several types of QoS policies (see Table: QoS Policy Types and Descriptions for summaries and references to details):

• service ingress (also known as access ingress)

• service egress (also known as access egress)

• MC-MLPPP SAP egress

• network (for ingress and egress and ring)

  • IP interface type policy for network ingress and egress

  • ring type policy for Ethernet bridging domain on a ring adapter card

• network queue (for ingress and egress)

• slope

• ATM traffic descriptor profile

• fabric profile

• shaper

  Note:

  The terms access ingress/egress and service ingress/egress are interchangeable. The previous sections used the term access, and the sections that follow use the term service.

Service ingress QoS policies are applied to the customer-facing Service Access Points (SAPs) and map traffic to forwarding class queues on ingress. The mapping of traffic to queues can be based on combinations of customer QoS marking (dot1p bits and DSCP values). The number of forwarding class queues for ingress traffic and the queue characteristics are defined within the policy. There can be up to eight ingress forwarding class queues in the policy, one for each forwarding class.

Within a service ingress QoS policy, up to three queues per forwarding class can be used for multipoint traffic for multipoint services. Multipoint traffic consists of broadcast, multicast, and unknown (BMU) traffic types. For VPLS, four types of forwarding are supported (which are not to be confused with forwarding classes): unicast, broadcast, multicast, and unknown. The BMU types are flooded to all destinations within the service, while the unicast forwarding type is handled in a point-to-point fashion within the service.

Service ingress QoS policies on the 7705 SAR permits flexible arrangement of these queues. For example, more than one FC can be mapped to a single queue, both unicast and multipoint (BMU) traffic can be mapped to a single queue, or unicast and BMU traffic can be mapped to separate queues. Therefore, customers are not limited to the default configurations that are described in this guide.

Service egress QoS policies are applied to egress SAPs and provide the configurations needed to map forwarding classes to service egress queues. Each service can have up to eight queues configured, since a service may require multiple forwarding classes. A service egress QoS policy also defines how to re-mark dot1p bits and DSCP values of the customer traffic in native format based on the forwarding class of the customer traffic.

Network ingress and egress QoS policies are applied to network interfaces. On ingress for traffic received from the network, the policy maps incoming EXP values to forwarding classes and profile states. On egress, the policy maps forwarding classes and profile states to EXP values for traffic to be transmitted into the network.

On the network side, there are two types of QoS policies: network and network queue (see Table: QoS Policy Types and Descriptions ). The network type of QoS policy is applied to the network interface under the config>router>interface command and contains the EXP marking rules for both ingress and egress. The network queue type of QoS policy defines all of the internal settings; that is, how the queues, or sets of queues (for ingress), are set up and used per physical port on egress and per adapter card for ingress.

A ring type network policy can be applied to the ring ports and the add/drop port on a ring adapter card. The policy is created under the config>qos>network command, and applied at the adapter card level under the config>card>mda command. The policy maps each dot1p value to a queue and a profile state.

If GRE or IP tunneling is enabled, policy mapping can be set up to use DSCP bits.

Network queue policies are applied on egress to network ports and channels and on ingress to adapter cards. The policies define the forwarding class queue characteristics for these entities.

Service ingress, service egress, and network QoS policies are defined with a scope of either template or exclusive. Template policies can be applied to multiple SAPs or interfaces, whereas exclusive policies can only be applied to a single entity.

One service ingress QoS policy and one service egress QoS policy can be applied to a specific SAP. One network QoS policy can be applied to a specific interface. A network QoS policy defines both ingress and egress behavior. If no QoS policy is explicitly applied to a SAP or network interface, a default QoS policy is applied.

Table: QoS Policy Types and Descriptions provides a summary of the major functions performed by the QoS policies.